A device (10) is provided for facilitating insertion of a needle or a cannula into a vein of a patient. The device comprises a fluid chamber (23) adapted to be held in operable engagement with a surface of the patient's skin by a fastener (30/34/35) that extends about a limb of the patient. The device is adapted to create a volume of reduced pressure within the fluid chamber, so as to facilitate expansion of an underlying part of the vein. The device enables insertion of a needle or cannula into the expanded part of the vein, whilst the fluid chamber remains operably engaged with the surface of a patient's skin.
